Trade in falsified goods is booming worldwide. The new Directive 2011/62/EU aims to put a stop to it in the field of prescription drugs. Among other methods, it sees intelligent adhesive application as being a highly suitable option for guaranteeing the authenticity of pharmaceutical packaging and its contents, as Andreas Brandt, specialist in tamper evidence at Baumer hhs, explains.

The number of deaths attributable to falsified medicinal products and the high proportion of these ‘medicines’ in global trade underline the need to protect critical products by all available means. Consumers must be able to rely on the pharmaceutical integrity of a product.

Directive 2011/62/EU (with which the EU plans to protect us against falsified prescription drugs as of 2017) says: "Past experience shows that such falsified medicinal products do not reach patients only through illegal means, but via the legal supply chain as well. This poses a particular threat to human health and may lead to a lack of trust of the patient also in the legal supply chain."

Among other things, it prescribes the traceability of medicinal products and the control of pharmaceutical packagings. So, the manufacturers of pharmaceutical products and their packagings need to take action.

Tamper-evident adhesive closing is cost-efficient

Several advantages favour the use of adhesives for closing: they are very cheap, adhesive application does not impair the availability of the packaging lines, the packaging design does not need to be altered for the purpose of adhesive application and various kinds of adhesive with different properties can be used and combined.

A fundamental distinction is made between hot melts and cold glues. Hot melts are heated for application, whereas cold glues are dispersions applied at room temperature. Hot melts are frequently used for packaging. Their greatest advantages are their ease of use and rapid gluing. However, conventional hot melts do have one negative property: they can be reactivated by heat, meaning that folding cartons are not always reliably protected against manipulation.

In the case of cold glues, the water they contain evaporates following application, or it is absorbed by the material. The remaining polymers join the parts to be glued. Bonding takes considerably longer and has to be assisted by applying pressure. Once set, however, cold glue can no longer be reactivated. Fibres are torn out when the cartons are opened for the first time. In addition to which, the glue flap is damaged, a fact that cannot be concealed afterwards.

The ‘two-shot method’ combines the positive properties of hot melts and cold glues. A hot melt is used for rapid closing of the folding cartons, while a cold glue makes for irreversible closing.

When is each adhesive used?

All these adhesive methods basically comply with the standard, since the glued folding cartons are perceptibly damaged when opened. That leaves the question: when is each adhesive the ideal solution? Generally speaking, the type of packaging line and the targeted level of security are usually decisive when it comes to selecting the adhesive. Apart from that, there is no single answer. Rather, the conditions prevailing in production must be carefully analysed in each instance, at best jointly by everyone involved in the process: the manufacturers of the pharmaceutical products, packaging lines and adhesive-application equipment.

The most suitable tamper-evidence technology can be implemented in production in this way, smoothly and without any major interruptions.

As reliably as adhesive application systems work today, application of the adhesive still has to be consistently monitored for security reasons. Is there adhesive everywhere there should be? And only there? Sensors are a time-proven means for complete monitoring of adhesive application. They detect any faults in adhesive application and cause defective folding cartons to be ejected from the process.

On systems operating according to the fail-safe principle, the folding cartons are considered to be defective until such time as they have successively completed all the envisaged security checks successfully. Additional security features, such as seals and labels, can also be verified during this process. Special software evaluates the data generated. Here, too, the question arises as to which solution best suits the individual security requirements. Manufacturers of pharmaceutical packagings should discuss the answer to this question with the supplier of their adhesive application equipment.